14.16.630 Net/gross calculation.

Categorical pretreatment standards may be adjusted to reflect the presence of pollutants in the industrial user's intake water in accordance with the following:

(A) The industrial user must make application to control authority to obtain credit for intake pollutants calculated on a "net" basis.

(B) The industrial user must demonstrate that the control system it proposes or uses to meet applicable categorical pretreatment standards would, if properly installed and operated, meet the standards in the absence of pollutants in the intake waters.

(1) Credit for generic pollutants such as BOD, TSS and oil and grease shall not be granted unless the industrial user demonstrates that the constituents of the generic measure of the intake water and the user's effluent are substantially similar.

(2) Credit shall be granted only to the extent necessary to meet the applicable pretreatment standards, up to a maximum value equal to the influent value. Additional monitoring may be necessary to determine eligibility for credits and compliance with adjusted standard(s) under this section.

(3) Credit shall be granted only if the user demonstrates that the intake of water is drawn from the same body of water as that into which the city discharges or if the user is using reclaimed water supplied by the city. The Napa River is the body of water into which the city discharges.

(C) The applicable categorical pretreatment standards contained in 40 CFR subchapter N specifically provide that they shall be applied on a net basis.